Conventionally, a propulsion system for an aquatic vessel includes one or more propellers for propelling the aquatic vessel. However, in recent times, the marine industry is making new attempts to harvest wind power to propel such aquatic vessels. One area of specific interest to the marine industry is to develop Magnus-type rotors for use with aquatic vessels. The Magnus-type rotors are optionally configured for supplementing the propellers of the aquatic vessels. As a result of harnessing wind power, Magnus-type rotors show immense promise and potential for use with aquatic vessels.
Given the large size and weight of a Magnus-type rotor, manufacturers of Magnus-type rotors are continuously developing improved methods of designing and manufacturing rotor bodies for use with aquatic vessels. As such, manufacturers of Magnus-type rotors are often faced with challenges in maintaining various desirable structural properties and/or parameters in the Magnus-type rotors. Some examples of such properties optionally include, but are not limited to: a low weight, resistance to corrosion, a high structural integrity and/or stiffness of the rotor body, a uniform mass distribution in the rotor body across various cross-sectional and/or symmetrical planes thereof, and balanced weight of the rotor body under operation.
A U.S. patent application 2009/0025304 (hereinafter referred to as '304 Publication) relates to methods of manufacturing large cylindrical objects from segmented components. However, such methods of manufacturing are potentially not applicable in a case of the rotor body, because Magnus-type rotors are typically required to operate in conditions that are different to those of the cylindrical objects described in the '304 publication. For example, the Magnus-type rotors are potentially required to rotate at high speeds and/or varying load conditions.
The published patent application WO2013/110695 discloses a Magnus effect rotor where the rotor is allowed to be displaced towards the deck of the vessel in an inoperable state. The construction of the rotor there is a rigid cylinder which is made up of cylindrical sections. The cylindrical sections are made up of plates, which plates are assembled into longitudinally connected cylindrical body sections.
The published patent application US2013/0055944 discloses manufacturing of a Flettner rotor. The rotor is formed by element comprising individual sheets or bands welded together or otherwise joined in order to present a continuous, smooth, largely cylindrical surface.
Also in published patent application US2013/0239859, a Magnus rotor is disclosed which has guide rollers and covers. This construction has covers that prevent foreign bodies passing into the drive of the rollers and also prevents operating personnel being injured.
Typically, in some cases, manufacturers employ a single-piece casting technique in which an entire rotor body is cast as a single unit for use with a support tower of the Magnus-type rotor. In other cases, manufacturers alternatively employ a half-shell casting method in which two halves of the rotor body are individually cast and then joined together to make up a total volume of the rotor body. However, with the use of such techniques, large molds and associated system hardware or equipment are potentially required. Moreover, time and labour required to manufacture the rotor body is often high. Furthermore, costs associated with manufacturing, assembling, and logistics handling of the rotor body are also potentially high.
The aforesaid previously known techniques do not allow the manufacturing process to be controlled for obtaining or achieving desirable structural properties. For example, rotor bodies produced from such previously known techniques potentially have a non-uniform mass distribution and/or a non-consistent stiffness in various cross-sectional and/or symmetrical planes of the rotor body. Consequently, the rotor bodies produced from such previously known techniques are potentially subject to detrimental effects such as, but not limited to, uneven rotation, wobbling, and/or deformation in shape of the rotor body during operation.
Therefore, taking into account the aforementioned drawbacks, there exists a need for a method of manufacturing a rotor body, whereby a manufacturer is able to control easily the processes of manufacturing the rotor body to obtain desirable structural characteristics therefrom. Moreover, there also exists a need for constructing a rotor body of even mass distribution, low weight, high and uniform stiffness, while entailing reduced costs, and less time and effort associated with manufacturing, assembling, logistics handling and operating of associated Magnus-type rotors.